Microwave cooking has become popular as an alternative to conventional thermal cooking methods which employ external heat sources. Cooking by microwave radiation involves the absorption of microwave energy directed at, and absorbed by, food which is being cooked. The energy imparted by the absorbed radiation causes molecular excitation that results in heating without an external heat source. Because much of the microwave radiation penetrates the surface of cooking foods and is absorbed beneath the surface, there is less disparity between the surface temperature and core temperatures of foods during microwave cooking than during thermal cooking where the food core is heated by heat transfer only. Thus, more uniform cooking results from microwave cooking.
Microwave cooking tends to progress at a much faster rate than thermal cooking. Because most microwave radiation is absorbed by the cooking foods, and because little heat is imparted to the atmosphere surrounding the foods, microwave cooking is more energy efficient than thermal cooking which heats a larger area and also heats materials other than the food to be cooked.
While the foregoing characteristics of microwave cooking are generally advantageous, some desirable characteristics of thermal heating are not easily duplicated. In particular, among the desirable characteristics imparted by thermal cooking which consumers have come to expect of cooked products are the characteristics of surface browning and crisping. It is believed that the relatively high surface temperatures and long cooking time of thermally cooked foods enhance the browning and crisping of food surfaces. Microwave cooking, in spite of its many advantages often involves insufficient cooking times and surface temperatures to achieve a degree of crisping and browning comparable to thermal cooking.
A number of solutions have been proposed for producing microwave-cooked products having desirable surface crispness and color which approximates the crispness and color achievable during thermal cooking. For instance, sauces which include sugars and amino acids have been used to coat chicken, chops, and the like for the purpose of achieving reactions which impart brown color. These browning sauces do not necessarily address the crispness problem. Moreover, moisture escaping from foods during cooking may inhibit the browning and may wash away and remove coating sauces. Spattering may also remove sauce from the food surface leaving inadequate amounts to achieve the desired browning and crisping.
Two-step processes have been proposed which involve roasting foods in hot fat to impart the desired crust and exposing the foods to microwave radiation for completing the cooking. However, such a two-step procedure eliminates the convenience which is a principle object of microwave cooking in the first place. That is, the additional cooking step diminishes the overall efficiency of the cooking process.
Other techniques previously proposed for enhancing crisping and browning in microwave cooking include modifications in the microwave heating apparatus to alter the environment around foods as they are cooked by, for instance, adjusting humidity to a predetermined level.
In U.S. Pat. No. 4,518,618, coating sauces are disclosed having combinations of certain salts which are said to increase surface absorption of microwaves and to increase surface temperature during cooking. Sauces containing these salts and other basic materials such as bread crumbs, maltodextrins and bran flakes are said to increase the crispness and brownness of microwave-cooked products. The patent does not address the problem of reduced sauce effectiveness which may be caused by spattering or by moisture escaping from the foods being cooked. Moreover the presence of a high salt concentration is undesirable for most food products. Indeed many health-conscious individuals prefer to avoid large quantities of salt in their diets.
Thus there remains a need for a moisture-resistant, spatter-resistant composition for imparting desirable brown color and crisp texture to the surface of microwave-cooked foods without elaborate modifications to the cooking apparatus, without adding multiple cooking steps, and without adding compounds which adversely affect palatability or desirability of foods to consumers.
It is an object of the instant invention to provide microwave cooking sauces capable of imparting desirably brown color and crisp texture to the surface of foods coated with said sauces and cooked by microwave.
It is another object of the invention to provide sauces which adhere well to foods on which they are coated and which resist spattering throughout the cooking process.
It is another object of the invention to provide sauces which help seal in the natural moisture of cooked meats and other food products.
It is another object of the instant invention to provide microwave cooking sauces which are effective in imparting crispness and brownness to even those foods which emit substantial amounts of water during cooking.
Other objects and advantages of the invention will become apparent from a thorough reading of the instant specification.